[lammps-users] liquid -> vapor (Argon) temperaturn drop immediately?

Why temperature drop down when liquid argon change to be vapor? and saturation temperature turns to be 110K around under 1atm?
It seems temperature response a little bit slower than volume expansion.

See Scripts below, thank you for your attention.

dimension 3
boundary p p p
units metal
communicate single vel yes

atom_style atomic
neighbor 2.0 bin
neigh_modify every 20 delay 0 check yes

lattice fcc 5.74
region rec block 0 10 0 10 0 10 #23.68 0 23.68 0 23.68 #0 20 0 20 0 20

create_box 2 rec
create_atoms 1 box

mass 1 39.95
mass 2 39.95

pair_style lj/cut 9.5

pair_coeff * * 1.04e-2 3.405 9.5

velocity all create 85.0 482748 #83.8K melting 87.3 boiling

minimize 1.0e-4 1.0e-6 100 1000
fix 4 all npt temp 85.0 85.0 0.02 iso 0.0 0.0 0.08 tchain 10 pchain 10 mtk yes tloop 10 ploop 10 drag 2.0 # 0.002388 0.002388 0.01 drag 2.0

timestep 0.001
thermo 100
dump 1 all atom 5000 atom.lj
run 100000

unfix 4

undump 1

fix 5 all npt temp 85.0 180.0 0.08 iso 0.0 0.0 0.080 tchain 10 pchain 10 mtk yes tloop 10 ploop 100 drag 2.0
timestep 0.001
thermo 10
dump 2 all atom 5000 TEST.metal
run 200000

Sincerely, yours

Email: [email protected]…8… / [email protected]…127…
Cell: 573-864-5846
Mechanical & Aerospace Engineering,
College of Engineering,
University of Missouri - Columbia

Your question is somewhat vague. Isn't it a physical
effect for the temperature of the remaining liquid
to drop when evaporation takes place?

Steve

2011/1/25 毛益进 <[email protected]>: